/ JJazzLab-X
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JJazzlab 3

Where to start?

Try this very short video tutorial.

What is JJazzLab?

🎵 JJazzLab is a desktop application which automatically generates backing tracks for any song, even complex ones. It’s a jam buddy to have fun improvising at home, learn new stuff or just practice your instrument. It’s also a great tool for teachers.
🎷 JJazzLab is designed to make non-boring backing tracks, backing tracks with variety, rhythmic accents and dynamics. You can start a solo slowly and gradually build up the atmosphere!
💻 Thanks to the underlying JJazzLab-X open-source platform developers can easily add new features and new music generation capabilities.


Backing tracks

  • Instant generation of a Midi backing track with drums, percussion, bass, piano, guitar, pad, horn section, …
  • Fine tuning of the backing track per song part: rhythm variation, intensity, muted instruments, drum fills, tempo factor, custom phrases, drums transform…
  • Play from anywhere, loop selected bars
  • Play transposed (e.g. for sax or trumpet players)
  • Any song structure: intro, chorus, 1st coda, etc.
  • Adjust tempo, transposition, choose and solo/mute instruments
  • Import user tracks
  • Support for multi-rhythm backing tracks, possibly with different time signatures
  • Export to Midi file, the full backing track or a single instrument track
  • Easy Midi-to-MP3 conversion via export to Midi file
  • Customizable click and pre-count


  • Chord lead sheet editor, song structure editor, chord symbol editor, mix console, song memo editor
  • Multi-file editor with dockable windows
  • Intuitive user interface with unlimited undo/redo, copy/paste between songs
  • Free placement of the chord symbols (quantified or not), off-beat chord symbols anticipation
  • Support all pop-rock and jazz chord symbols, plus user-defined chord symbols
  • Edit chord symbol musical rendering: underlying harmony, accent type, harmony variation during solos, chord symbol substitution, …
  • Drag & drop support to import/export Midi files
  • Customizable song template
  • Customizable UI colors and fonts
  • Print chord lead sheet and song structure


  • Support for Yamaha style files (SFF1 & SFF2 format), access to thousands of free styles on the web
  • Hundreds of embedded rhythms in the installer
  • Support for “YamJJazz Extended Yamaha" style files for even more variations per style
  • Open architecture: new rhythm generation engines can be easily added via plugins

Notes viewer

  • Show backing track notes in real time
  • Show selected chord symbol notes and scales
  • Piano keyboard
  • Guitar diagrams with most common chords, open/close voiced chords, inversions

(pseudo) Arranger keyboard mode

  • Recognize chords played on Midi IN and update the backing track in (pseudo) real-time

Improvisation help

  • Automatic generate improvisation guides on your chord leadsheet
  • Based on Hal Crook's reference book "How to improvise"


  • Connect to any audio engine via Midi: SoundFont player (recommended with the JJazzLab SoundFont), Java internal synth, external synth, VST host via virtual Midi port such as ‘LoopBe1’
  • Compatible with GM/GM2/XG/GS instruments
  • Compatible with any Midi instrument via Cakewalk instrument definition files (.ins)
  • Automatic drums/percussion drum map remapping from Yamaha XG key map to GM/GM2/GS key maps
  • Optimized JJazzLab SoundFont for a high-quality rendering and automatic instrument selection
  • Ready-to-use presets for VirtualMidiSynth (Windows) and FluidSynth (Linux)
  • User-defined default mix per rhythm
  • User-defined default instruments


  • Band-In-A-Box lead sheet files
  • musicXML lead sheet files
  • Impro-Visor lead sheet files


  • Song memo with hyperlinks opened upon song loading
  • Easily add new features thanks to the open-source pluggable architecture
  • Based on the Netbeans application framework
Last modified 1yr ago